Lens Construction

What should one be looking for when reading about lens construction?

What is the significance of elements and groups, and the number of diaphragm blades?

Is the angle of view the amounts that the lens can view from the centre point to the right or left (also up or down) or does it refer to something I have never thought of?

You will be pleased to hear I think I understand the rest but would not be surprised if I don't

Elements are the pieces of glass in the lens & groups are 'groups' of elements fixed together. Complex zooms tend to have more elements and groups than say a prime lens. The more elements and groups a lens has the more expensive it tends to be although it doesn't always mean the quality is better as every time light goes through glass, air, glass - the more opportunity there is for reflections and lens flare.

The number of Diaphragm blades - (I think) affects the way the 'out of focus' appears. The more blades you have the 'rounder' the hole giving you a softer more gradually blurred out picture.

Thank you Phil, I can understand the aperture blades that makes sense. But all lens quote the elements and their grouping as if it meant something I should be aware of but from what you say it is not really significant data, that I understand too, as the quality of the glass and the skill in putting together would make the difference between a quality lens and a milk bottle.